My Uncle also did not believe in tree stands, except for archery. He also thought everyone should use a lever action and open sights. IMO, the addl hunting pressure in most areas make it near impossible to be successful w/o a tree stand, and many places (woods) just seem more over grown than they used to be, making one necessary.
Re sporting: It is easier to hunt a farm w/o a tree stand than it is to hunt in woods with a tree stand. The deer are more used to human scent, and it does not bother them as much (on a farm). My cousin (who grew up on a farm) used to tell me that if you want to get a deer, just ride out on a tractor, they won't even move!
IMO, tree stands are necessary for bows and cross bows, and with fire arms they make the sport safer (the shot is always going toward the ground) and they result in more clean one shot kills, so in that regard they are more sportsmanlike. That said, I have harvested deer still hunting with a bow, including my biggest deer. Unfortunately, addl hunting pressure (and illegal baiting) have made this method very unproductive in the areas I hunt. I wish it were not that way, but I have to deal with reality. I'm primarily a meat hunter, and I want more than one a decade in the freezer.
Nothing personal, but as long as we obey the law, take your own road. I love to still hunt, but unless it is in a remote area or late in the season, I won't do it as it usually just results in pushing the deer to someone else. I also choose based on conditions. If there is a powdery snow on the ground, I love to still hunt, if it is dry and noisy, I like to sit in a tree stand and listen for them (I'll usually hear them before I can see them).
You could also call long range shooting and deer drives un sportsmanlike, but they are the only way you will harvest some deer. Like I said, take your own road. Tree stands and scopes make it safer and result in more one shot kills. IMO, that is more sporting. Still hunters with open sights often did a lot of tracking.